British Pat. No. 2,116,990 (also U.S. Defensive Publication T103,703) to ICI and H. M. Colquhoun, Polymer Preprints, 25 (2), 17-18 (1984), disclose a process for the preparation of poly(ether-ketones) (a) from dicarboxylic acids and aromatic compounds, (b) from monocarboxylic acids or (c) from a mixture of (a) and (b). The process disclosed in these references (1) does not utilize an oxide of phosphorus and/or a perhaloalkanoic anhydride in any way, (2) is limited to special `activated` dicarboxylic acids, monocarboxylic acids, and aromatic compounds, and (3) does not include such common dicarboxylic acids as terephthalic and isophthalic acids and such aromatic compounds as diphenyl ether or biphenyl (see page 2, lines 55-67, of the British patent). In Example 6 of the British patent, an attempt is made to prepare a poly(ether-ketone) by reacting terephthalic acid and p-diphenoxybenzene in only trifluoromethanesulfonic acid at ambient temperature for 48 hours. No increase in solution viscosity was observed. Subsequently, the mixture was heated to 90.degree. C. for 5 hours with only a slight increase in solution viscosity apparent. The Colquhoun reference paper states, in Column 2 of page 17, that "Terephthalic acid, for example, fails to react at all with aryl ethers in CF.sub.3 SO.sub.3 H, . . . . "
U.S. Pat. No. 4,396,755 discloses a process which involves the polymerization of (a) a dicarboxylic acid(s) with an aromatic compound(s), (b) a self-polymerizable aromatic monocarboxylic acid, or (c) a mixture of (a) and (b) in the presence of a fluoroalkanesulfonic acid and a quinquevalent phosphorus halide, such as PCl.sub.5. According to Column 2, lines 20-21, "Presumably, the reaction proceeds via the in-situ formation of mono- or diacyl halide." (Di)carboxylic acid halide(s) are well known intermediates for the preparation of polyketones (see U.S. Pat. No. 4,398,020).
British Pat. No. 2,099,006 discloses a process for the preparation in trifluoromethanesulfonic acid of poly(ether-ketones) from monocarboxylic acid chlorides (such as 4-phenoxybenzoyl chloride) in which P.sub.2 O.sub.5 and water may, if desired, be added to the polymerization reactor in order to produce phosphoric acid (to act as a solvent) (see lines 27-41 on page 1 and lines 1-8 and 17-20 on page 2). In this case, however, only the acid chlorides, which are appreciably more reactive than the carboxylic acids, are disclosed. The use of monocarboxylic or dicarboxylic acids is not disclosed.
European Patent Application No. 75,390 discloses the acylation of aromatic compounds to produce "arylophenones" by the reaction of an aromatic carboxylic acid with an aromatic compound in the presence of a fluoroalkanesulfonic acid. This reference does not disclose either the preparation of high molecular weight poly(ether-ketones) or the use of a phosphorus compound and/or a perhaloalkanoic anhydride in combination with a perfluoroalkanesulfonic acid.
European Patent Application No. 241,306 discloses the synthesis of polyaryletherketone by Friedel-Crafts chemistry using a catalytic quantity of a strong acid, such as trifluoromethanesulfonic acid, in a solvent of lower acidity preferably comprising a second acid of strength at least equal to chloroacetic acid. This reference neither discloses nor contemplates the preparation of poly(ether-ketones) from dicarboxylic acids and the bis(4-phenoxybenzoyl)hydrocarbons described hereinbelow. The reference also fails to disclose the preparation of a poly(ether-ketone) from dicarboxylic acids in which the reaction solvent is a perfluoroalkanesulfonic acid containing a phosphorus and/or perhaloalkanoic anhydride.